Applicants"" invention relates to a method to partition a data storage and retrieval system into one or more logical libraries. Applicants"" invention further relates to a data storage and retrieval system which includes a computer useable medium having computer readable program code disposed therein for partitioning Applicants"" data storage and retrieval system into one or more logical libraries. Applicants"" invention further relates to computer program product usable with a programmable computer processor having computer readable program code embodied therein for partitioning a data storage and retrieval system into one or more logical libraries.
Automated media storage libraries are known for providing cost effective access to large quantities of stored media. Generally, media storage libraries include a large number of storage slots in which are stored data storage media. The portable data storage media are typically housed in a portable container, such as a tape cartridge, an optical cartridge, and the like. One (or more) accessors typically access the data storage media from the storage slots and delivers the accessed media to a data storage drive for reading and/or writing data on the accessed media. Suitable electronics operate the accessor(s) and operate the data storage drive(s) to transmit to, and/or to receive data from, an attached on-line host computer system.
In a conventional automated media storage library, the storage slots are arranged in a planar orthogonal arrangement forming a xe2x80x9cwallxe2x80x9d of storage slots for holding data storage media. The plane may be a flat plane, or may be a cylindrical plane. To double the storage capacity, two xe2x80x9cwallsxe2x80x9d of storage slots may be provided on either side of the accessor.
A number of different companies manufacture automated media storage libraries today, each model displaying various different features. One example is the IBM 3494 Media Storage Library. Some of the automated media storage libraries have dual or multiple accessors to provide a level of redundancy and/or improved performance.
It would be advantageous to be able to share a data storage and retrieval system among multiple hosts and therefore amortize the cost of that system more widely. It is often difficult, however, to design components that can respond to multiple hosts. Sharing a data library using prior art apparatus and methods generally requires that special host software be installed on each host computer. Such software allows communication between differing hardware platforms using differing operating systems. In addition, using prior art methods such library sharing generally requires the addition of a cumbersome layer of supervisory software code in the library, which both increases the need for processing capability of the library and which can ultimately reduce the performance of other aspects of the library. Requiring end-users to develop software for an automated data storage and retrieval library to enable multiple incompatible hosts to manage a shared inventory may require a redesign of the library programming and may be sufficiently expensive as to be prohibitive for the low cost environment.
In the low cost environment where hosts and libraries alike often comprise mass produced devices what is needed is an easy-to-use, automated process, to partition a data storage and retrieval system into one or more logical libraries thereby achieving a library sharing capability which does not require special host software or modification to any of the components of the mass produced data storage and retrieval system. Applicants"" method to partition a data storage and retrieval system into one or more logical libraries fulfills these requirements. In addition, Applicants"" method comprises an automated process which prevents a user from incorrectly configuring Applicants"" data storage and retrieval system.
Applicants"" invention includes a method to partition a data storage and retrieval system into one or more logical libraries, where that data storage and retrieval system includes a library controller, at least one data storage drive and at least one control port. A control port provides a control path into the data storage and retrieval system. Devices such as control ports and data storage drives are arranged in device slots by the library manufacturer, and/or by the user, and/or by repair personnel. Using Applicants"" method, a data storage and retrieval system can be partitioned into smaller virtual libraries called logical libraries.
A logical library comprises a subset of the complete physical data storage and retrieval system, where that logical library includes at least one data storage drive and at least one control port. In other words, storage slots, data storage drives, and control ports disposed in a data storage and retrieval system can be partitioned into smaller logical libraries which share common robotic resources, i.e. robotic accessors. Applicants"" method includes the steps of identifying each of the control ports and data storage drives, determining the number of potential logical libraries that could be configured using those control ports and data storage drives, selecting the number (N) of logical libraries to configure, and partitioning the data storage and retrieval system into those (N) logical libraries.
Applicants"" invention further includes a data storage and retrieval system which includes a computer useable medium having computer readable program code disposed therein for partitioning Applicants"" data storage and retrieval system into one or more logical libraries. Applicants"" invention further includes a computer program product usable with a programmable computer processor having computer readable program code embodied therein for partitioning Applicants"" data storage and retrieval system into one or more logical libraries.